It can be useful to pull cables in different applications. For example, in pipe bursting, a pipe bursting head can be pulled through an existing pipe in the ground to burst the existing pipe. To pull the bursting head, a pulling apparatus using hydraulic cylinders may be positioned at one end of a pipe and used to pull a cable attached to the bursting head from an opposite end of the pipe. A pipe bursting head is a device that is sized and configured to burst a pipe as the pipe bursting head is pulled through the pipe. One example of a bursting head can have a generally conical shape with a minimum diameter that fits inside the pipe and a maximum diameter that exceeds the diameter of the pipe. Bursting heads can also include fins that are sharp and concentrate stress at one or more locations on the inside of the pipe to encourage the pipe to fracture as the bursting head is pulled through the pipe. The bursting head can be attached to a replacement pipe so that as the existing pipe is burst, the new pipe can be pulled in behind the bursting head.
A center hole ram is an existing type of ram with a piston that defines an axial hole passing through the piston in a direction of the piston's travel. The hole through the piston may be in any of various different shapes, and the hole may or may not be centered in the ram or in the piston itself.